A United Nations report into the Nauru prison camp has raised "profound" concern over the inhuman and degrading treatment of refugee children there, which it says is having an impact on their physical wellbeing.

About 500 people, including 50 children, are stuck in a prison on the tiny Pacific Island nation as they seek asylum in Australia.

The UN Committee on the Rights of the Children said in its report that the refugees face persistent discrimination, and are living in cramped, humid and life-threatening conditions.

"The Committee is concerned at the lack of a comprehensive policy to specifically promote and protect the rights of children," the report said. "It also notes with concern reports indicating that the Child Protection Directorate staff lack training or formal experience in child protection/child welfare."

The report added that such conditions could exacerbate mental health issues, and that the agreement between the governments of Australia and Nauru failed to take into account the best interests of children.

UN workers are also "seriously concerned" that NGOs and journalists have been restricted in their ability to conduct research relating to children's rights at the prison.

Nauru, the report said, should prioritise the immediate transfer of children and their families into a permanent resettlement option.

Al Jazeera's Andrew Thomas, reporting from Sydney, said: "In 17 pages of this report, the committee says how concerned it is 35 times ... Will this change anything? There have been lots of previous reports about abuse on Nauru. Former workers there have told Al Jazeera how bad conditions there are, but Australia's government dismisses those claims."

Government officials say allegations are not evidence and that its policies are useful in controlling immigration, added Thomas.

The governments of Nauru and Australia did not respond to a request for comment from Al Jazeera by the time of publication.

"The real solution [to the refugee crisis] is to return refugees to whence they came," said Jim Saleam, president of the far-right Australia First Party. "The claims of persecution that are generally made, we regard as massively exaggerated."

Nauru is a tiny 29sq kilometre island in the middle of the Pacific Ocean.

Nauru's prison camp first opened in 2001, under a policy brought in by Australia's conservative Liberal Party - the so-called Pacific Solution.